High-Throughput in Situ Characterization of Polymer Crystallization under an Intense Flow, High Pressure, and Cooling Gradient during Injection Molding

Injection molding is a polymer-processing method widelyused, whichconsumes about one-third of global plastics and produces 80% of plasticparts. However, it is still challenging to in situ reveal the structuralevolution of polymers during injection molding, which is a long-standingobstacle to understand the relationship of processing-structure-property.This work has first built an in situ investigation system with theaid of a highly brilliant synchrotron X-ray and large experimentalspace with a length of 30 m, width of 8 m, and height of 6 m, allowingthe installation of an industrial-scale injection molding machine.Based on the characterization system, the fast millisecond-resolvedstructural evolution of general semicrystalline polymers is identified.Various structural types of information including crystallizationkinetics, polymorphism, and the growth and orientation of their lamellarcrystals under an actual environment of non-isothermal crystallizationwith a cooling gradient, intense flow, and high pressure during injectionmolding have been revealed for the first time. The high-throughputfeature of the system provides a vital prerequisite for the subsequentestablishment of a quantitative database of processing parameter-structure-performanceand the precise regulation of polymer aggregation structures, whichis valuable for the digitalization and intelligence of the developmentof the injection molding industry and integration into the IndustrialInternet.